It is common practice to provide interior and exterior doors of buildings with knobs which must be rotated to effect opening of the doors. Rotation of a door knob is not a simple undertaking for many persons, such as those afflicted with arthritis or whose hands or arms are otherwise handicapped. A rockable lever is more easily manipulated by such persons, but by the time the handicap of some persons mainfests itself the doors of the building occupied by such persons may already be fitted with rotary knobs. The expense of replacing rotary knobs with rockable levers may be beyond the means of many persons who could desire such replacement.
The desirability of converting rotary knobs to rockable levers by the attachment of a lever to a rotary knob has been recognized heretofore. Typical of conversion devices heretofore proposed are those disclosed in Sutter U.S. Pat. Nos. 2,756,088 and 2,801,122; Hohl U.S. Pat. No. 3,575,453; and Overholser U.S. Pat. No. 3,827,739. Although the constructions disclosed in these patents enable a rotary knob to be converted to a rockable lever, each of such constructions requires the use of one or more tools to effect the conversion. Quite often, the person who desires to make the conversion is incapable of using the necessary tools, thereby requiring the assistance of some other person.
Another objection to conversion devices of the kind heretofore proposed is that, when such devices are installed, some or all of the mounting means is visible, thereby detracting from the appearance of the door knob and the door on which it is mounted.
An object of the present invention is to provide a lever attachment adapted to be fitted to a rotary door knob and which requires the use of no tools in mounting the attachment on the knob.
Another object of the invention is to provide an attachment of the kind referred to and wherein the mounting means is invisible or disguised.